2002 Dodge Ram 1500 voltage meter and check engine light will come on. While driving or sitting idle. What do you think it is?

Alternator is probably ready to go. Bring to Autozone have them test it for you. Should be putting out at least 14 volts. Also have them test your battery with the engine off. You may have a very weak battery.

another way to check if its the alternator is start the truck and disconnect the positive battery post if it dies then alt. is shot and should be replaced.

I did go to autozone and all checked good. I replaced the neg battery cable along with the positive cable from what I think is called a Diode??? There were two on the positive cable. When I went to go take them off, one cable fell out so I'm sure there was not a good connection there. I then cutting of bottom cable and reconnected in new diodes and new battery cable. Also cleaned post real good. As of now lights are brighter and not shaking. She drove to work and no dash lights came on. So I hope this is it. If not even though they say alt. is ok and I did take the battary cable off and truck stayed running I do not know what will be next. I hope nothing. Thanks guys for your input.

I was raised a gear head as a teenager. My brain don't work as well now. Being female has its disadvantages and I hate shops.

Yeah, shops love putting the screws to the women....